diff --git a/configure.ac b/configure.ac
index e57588144a..5ea7708f7d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@ dnl Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson
 dnl Copyright (c) 2007-2015, The Tor Project, Inc.
 dnl See LICENSE for licensing information
 
-AC_INIT([tor],[0.2.6.6])
+AC_INIT([tor],[0.2.6.6-dev])
 AC_CONFIG_SRCDIR([src/or/main.c])
 AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE